Adjectives must agree in gender (masculine or feminine) and number (singular or plural) with the noun they describe, and they are placed after the noun.
In general, masculine adjectives end in -o and feminine adjectives end in -a: blanco and blanca (white).
Adjectives that end in -ín, -án, -ón, -dor, -tor and -sor in the masculine will add an -a for the feminine.
Adjectives that end in -ete for the masculine will end in -eta for the feminine.
Adjectives of nationality add -a to the masculine to form the feminine: francés – francesa (French).Notice that when you add -a, the adjective is no longer written with an accent.
To form the plural of adjectives, follow the same rules for forming the plural of nouns.
Most adjectives follow the noun they describe, but the following adjectives drop the final -o if placed before a masculine noun in the singular: bueno – good; malo – bad; alguno – some; ninguno – no, any; uno – one; primero – first; tercero – third
When grande means great, it precedes the noun and drops the -de before a singular noun of either gender. Santo (saint) drops the -to before all masculine nouns, except those beginning with Do- or To-.
Word Document at: 055 Spanish Preceding Adjectives